Wet deposition fluxes of atmospheric inorganic reactive nitrogen at an urban and rural site in the Indo-Gangetic Plain

Abstract Very limited information on the magnitude and environmental impacts of both inorganic as well as organic forms of Nitrogen (N) wet deposition is available in India. Molar concentrations of inorganic (NH4+ and NO3−) and organic N in rainwater were monitored at three different land-use sites in Indo-Gangetic Plain (IGP) during the monsoon period (June-September) of 2017. It has been observed that dissolved organic N (DON) contributed significantly to the total dissolved N (TDN) ranging from 5–60%. Dissolved inorganic N (DIN = NH4+ + NO3−) concentration was recorded as high as 221.0 µmol L− 1 at urban site to as low as 65.9 µmol L− 1 at the rural site. A similar pattern was also observed for DON. NH4+ contribution to TDN had the order: urban megacity (65%) > urban (70%) > rural (75%). Agriculture and animal husbandry are the primary sources of NH4+ emissions in the rural site. However, NO3− has shown a contrasting trend at these sites (25%, 15% and 8%, respectively). Wet deposition fluxes of atmospheric TDN was observed to be higher at urban sites. This can attributed to a variety of local sources such as vehicular emission, microbial emissions, biomass burning, human excreta due to higher population density, and transportation from surrounding areas, as observed from concentration weighted trajectories (CWT) model and cluster analysis. Upwind region of IGP has experienced major influence of air mass transported from agriculturally rich northwest part of India. However, both the downwind sites have experienced by-and-large the influence of south-westerly air-masses originated over the Arabian Sea. Study has found that the DON contributes significantly to TDN and need to be included for budget assessment in South Asia.

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Dry deposition fluxes of NH4+-N and NO3--N at a rural site of Indo-Gangetic Plain, India.

10.5194/egusphere-egu21-7776 ◽

2021 ◽

Author(s):

Moh Naseem ◽

Umesh Kulshrestha

Keyword(s):

Size Distribution ◽

Dry Deposition ◽

Major Ions ◽

Dominant Mode ◽

Dust Particles ◽

Rural Site ◽

Gangetic Plain ◽

Strong Base ◽

Deposition Fluxes ◽

Indo Gangetic Plain

The world&#8217;s acute reactive nitrogen (Nr) deposition is chronically eroding the biospheric integrity and undermining earth system&#8217;s resilience to be in an accommodatable state. The present study comprehensively attempts to decipher the dry depositions of atmospheric inorganic Nr along with other major ions through dustfall fluxes. Authentic atmospheric dust samples were collected by incorporating a surrogate-surface approach at an agriculturally intensive rural site in Indo-Gangetic plain of India over a year-long temporal scale from October 2017-September 2018. The mean (&#177;Standard Error) dry deposition fluxes of NH4+-N and NO3--N during the whole study period were observed as 0.41&#177;0.09 kg ha-1 yr-1 and 6.51&#177;1.58 kg ha-1 yr-1, respectively. The total percent ionic contribution to the dustfall flux was observed 2.95% and the descending order of their percent contribution in total ionic fluxes were observed as SO42- (31.46%) > Cl- (15.74%) > K+ (15.04%) > Ca2+ (13.97%) > Na+ (10.23 %) > NO3- (7.06%) > Mg2+ (4.43%) > F-(1.62%) > NH4+ (0.44%). The relative dominance of NO3--N over NH4+-N fluxes was maintained in all seasons during the whole monitoring period which could be attributed to the competitive exclusion of NH4+-N from acid-base neutralization reactions by other strong base cations in dustfall. Size-distribution and morphological analysis of dust particles from Scanning Electron Microscope images signified the anthropogenic involvement in shaping the dominant mode of particle-size distribution in dust fall fluxes which culminated into the dominance of fine-mode fraction over course-mode in dustfall.

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Spatio-Temporal Variation of Atmospheric Gaseous and Particulate Reactive Nitrogen over Northern India

Current World Environment ◽

10.12944/cwe.16.special-issue1.05 ◽

2021 ◽

Vol Special Issue (1) ◽

pp. 53-67

Author(s):

Manisha Mishra ◽

Umesh C Kulshrestha

Keyword(s):

Source Parameters ◽

Ambient Air ◽

Water Soluble ◽

Rural Site ◽

Urban Site ◽

Local Source ◽

Reactive Nitrogen ◽

Gangetic Plain ◽

Reactive N ◽

Spatio Temporal

The present study reports spatio-temporal distribution pattern of major gaseous (NH3 and NO2) and particulate water soluble total nitrogen (pWSTN) in the ambient air to explore the seasonal variation, major interactions and dominating sources. Considering the major hotspot of atmospheric reactive nitrogen (N) emission, three sites in Indo-Gangetic plain (IGP) were selected based on different local source parameters. Results have shown that gas phase reactive N contribute up to 90% of total analyzed reactive N, where NH3 imparted highest at all the three sites. Prayagraj, a fast growing urban site, has shown highest concentrations of NH3 (72.0 μg m−3), followed by Madhupur rural site (57.7 μg m−3) and Delhi, an urban megacity site (35.8 μg m−3). As compared to previous studies conducted at different sites of IGP, NH3 concentrations were reported to be the highest at the former two sites. However, unlike NH3, NO2 levels were recorded lower at Madhupur (3.1 μg m−3) and Prayagraj (9.4 μg m−3) sites as compared to Delhi (13.4 μg m−3). Similarly, pWSTN concentrations were in the order of Madhupur (6.6 μg m−3) < Prayagraj (10.0 μg m−3) < Delhi (10.1 μg m−3). A strong correlation of NO2 with pWSTN at urban sites has shown the crucial role of NO2 in the formation of nitrogenous aerosols. Significant spatial variation can be attributed to varying local emission sources ranging from microbial emission from improper sewage treatment and open waste dumping at Prayagraj, agricultural activities at Madhupur and vehicular exhausts at Delhi site.

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Wet deposition of total dissolved nitrogen in Indo-Gangetic Plain (India)

Environmental Science and Pollution Research ◽

10.1007/s11356-021-16293-0 ◽

2021 ◽

Author(s):

Manisha Mishra ◽

Umesh Chandra Kulshrestha

Keyword(s):

Wet Deposition ◽

Gangetic Plain ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

Indo Gangetic Plain

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Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: Influence of biomass burning

10.5194/acp-2016-1176 ◽

2017 ◽

Cited By ~ 1

Author(s):

Xin Wan ◽

Shichang Kang ◽

Quanlian Li ◽

Dipesh Rupakheti ◽

Qianggong Zhang ◽

...

Keyword(s):

Biomass Burning ◽

Vanillic Acid ◽

Monsoon Season ◽

Syringic Acid ◽

Rural Site ◽

Aerosol Composition ◽

Gangetic Plain ◽

Post Monsoon ◽

Post Monsoon Season ◽

Indo Gangetic Plain

Abstract. To better understand the characteristics of biomass burning in the northern Indo-Gangetic Plain (IGP), total suspended particles were collected in a rural site, Lumbini, Nepal during April 2013 to March 2014 and analyzed for the biomass burning tracers (i.e., levoglucosan, mannosan, vanillic acid, etc.). The annual average concentration of levoglucosan was 734 ± 1043 ng m−3 with the maximum seasonal mean concentration during post-monsoon season (2206 ± 1753 ng m−3), followed by winter (1161 ± 1347 ng m−3), pre-monsoon (771 ± 524 ng m−3) and minimum concentration during monsoon season (212 ± 279 ng m−3). The other biomass burning tracers (mannosan, galactosan, p-hydroxybenzoic acid, vanillic acid, syringic acid, and dehydroabietic acid) also showed the similar seasonal variations. There were good correlations among levoglucosan, organic carbon (OC) and elemental carbon (EC), indicating significant impact of biomass burning activities on carbonaceous aerosol loading throughout the year in Lumbini area. According to the characteristic ratios: levoglucosan / mannosan (Lev / Man) and syringic acid / vanillic acid (Syr / Van), we deduced that the high abundances of biomass burning products during non-monsoon seasons were mainly caused by the burning of crop residues and hardwood while the softwood had less contribution. Based on the diagnostic tracer ratio (i.e., Lev / OC), the OC derived from biomass burning constituted large fraction of total OC, especially during post-monsoon season. By analyzing the MODIS fire spot product and five-day air-mass back trajectories, we further demonstrated that organic aerosol composition was not only related to the local agricultural activities and residential biomass usage, but was also impacted by the regional emissions. During the post-monsoon season, the emissions from rice residue burning in western India and eastern Pakistan could impact particulate air pollution in Lumbini and surrounding regions in southern Nepal. Therefore, our finding is meaningful and has a great importance for adopting the appropriate mitigation measures, not only at the local level but also by involving different regions and nations, to reduce the biomass burning emissions in the broader IGP region nations.

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Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: influence of biomass burning

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-8867-2017 ◽

2017 ◽

Vol 17 (14) ◽

pp. 8867-8885 ◽

Cited By ~ 51

Author(s):

Xin Wan ◽

Shichang Kang ◽

Quanlian Li ◽

Dipesh Rupakheti ◽

Qianggong Zhang ◽

...

Keyword(s):

Biomass Burning ◽

Vanillic Acid ◽

Monsoon Season ◽

Rural Site ◽

Aerosol Composition ◽

Gangetic Plain ◽

Minimum Concentration ◽

Post Monsoon ◽

Post Monsoon Season ◽

Indo Gangetic Plain

Abstract. To better understand the characteristics of biomass burning in the northern Indo-Gangetic Plain (IGP), total suspended particles were collected in a rural site, Lumbini, Nepal, during April 2013 to March 2014 and analyzed for the biomass burning tracers (i.e., levoglucosan, mannosan, vanillic acid). The annual average concentration of levoglucosan was 734 ± 1043 ng m−3 with the maximum seasonal mean concentration during post-monsoon season (2206 ± 1753 ng m−3), followed by winter (1161 ± 1347 ng m−3), pre-monsoon (771 ± 524 ng m−3) and minimum concentration during monsoon season (212 ± 279 ng m−3). The other biomass burning tracers (mannosan, galactosan, p-hydroxybenzoic acid, vanillic acid, syringic acid and dehydroabietic acid) also showed the similar seasonal variations. There were good correlations among levoglucosan, organic carbon (OC) and elemental carbon (EC), indicating significant impact of biomass burning activities on carbonaceous aerosol loading throughout the year in Lumbini area. According to the characteristic ratios, levoglucosan ∕ mannosan (lev ∕ man) and syringic acid ∕ vanillic acid (syr ∕ van), we deduced that the high abundances of biomass burning products during non-monsoon seasons were mainly caused by the burning of crop residues and hardwood while the softwood had less contribution. Based on the diagnostic tracer ratio (i.e., lev ∕ OC), the OC derived from biomass burning constituted large fraction of total OC, especially during post-monsoon season. By analyzing the MODIS fire spot product and 5-day air-mass back trajectories, we further demonstrated that organic aerosol composition was not only related to the local agricultural activities and residential biomass usage but also impacted by the regional emissions. During the post-monsoon season, the emissions from rice residue burning in western India and eastern Pakistan could impact particulate air pollution in Lumbini and surrounding regions in southern Nepal. Therefore, our finding is meaningful and has a great importance for adopting the appropriate mitigation measures, not only at the local level but also by involving different regions and nations, to reduce the biomass burning emissions in the broader IGP region nations.

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Study of MODIS derived AOD at three different locations in the Indo Gangetic Plain: Kanpur, Gandhi College and Nainital

Annales Geophysicae ◽

10.5194/angeo-30-1479-2012 ◽

2012 ◽

Vol 30 (10) ◽

pp. 1479-1493 ◽

Cited By ~ 29

Author(s):

P. Choudhry ◽

A. Misra ◽

S. N. Tripathi

Keyword(s):

Indian Subcontinent ◽

Rural Site ◽

Urban Site ◽

Gangetic Plain ◽

Large Variability ◽

Entire Area ◽

Aerosol Model ◽

Moderate Resolution Imaging Spectroradiometer ◽

A Site ◽

Indo Gangetic Plain

Abstract. Moderate resolution imaging spectroradiometer (MODIS) sensors, onboard Terra and Aqua, have been observing the Earth since start of 2000 and mid 2002, respectively. The present study provides a comparison of Collection 5 (C005), aerosol optical depth (AOD) retrieved by MODIS, with AERONET-observed AOD over Kanpur (an urban site), Gandhi College (a rural site) and Nainital (a relatively clean site) in the Indo Gangetic Plain (IGP). The results show that at Kanpur, MODIS retrievals are well within the prelaunch uncertainty ± 0.05 ±0.15 τ, and a good correlation (R2 > 0.7 for both Terra and Aqua). Nainital also shows good retrieval (R2 > 0.8 for Terra and R2 > 0.68 for Aqua), as more than 66% of total collocations are within the prelaunch uncertainty. However, it is seen that there is significant overestimation in this case, especially in the months of winter. Gandhi College poses a challenge to MODIS retrieval, as here <57% of MODIS-retrieved AOD values lay within the prelaunch uncertainty and the correlation is very poor (R2 ~ 0.5 for Aqua and R2 ~ 0.4 for Terra); also there is persistent underestimation in this case. Small value of slope shows that assumed model results in underestimation, and large intercept values for the linear regression fit show that errors due to surface reflectance are high here. Our comparison shows that MODIS retrieval works well over Kanpur, and Nainital with winter as an exception. However, MODIS retrieval is poor for Gandhi College which is a rural area. The aerosol properties at Kanpur are currently used as representative of the entire subcontinent in the MODIS C005 algorithm, which is not an accurate assumption. The large variability in land use and climate over India makes it a site too complex for a single aerosol model to be used over the entire area. Therefore further study with as many sites as possible over the Indian subcontinent would help provide more realistic modeling for the Indian subcontinent.

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Wet Deposition Fluxes of Nitrate and Ammonium at a Rural Agricultural Site in north India

10.5194/egusphere-egu21-9103 ◽

2021 ◽

Author(s):

Sudesh Yadav ◽

Umesh Kulshrestha

Keyword(s):

Wet Deposition ◽

Major Ions ◽

Monsoon Season ◽

North India ◽

Reactive Nitrogen ◽

Deposition Flux ◽

Deposition Fluxes ◽

Average Value ◽

Wet Deposition Flux ◽

Agricultural Site

The chemical composition of rainwater is an indicator of the air quality and sources of influence. In this study, pH and ionic concentrations were measured in rain samples collected during monsoon season of 2018 at a rural agricultural site located in northern part of India. Wet deposition fluxes of reactive nitrogen species NH4+ over NO3- were calculated to estimate their annual deposition. The pH of samples varied between 5.2 and 6.14, with an average value of 5.72 which is in alkaline range considering 5.6 as the neutral pH of cloud water with atmospheric CO2 equilibrium. These relatively high pH values indicate the neutralisation of acidity in precipitation. Samples were analysed for their cationic and anionic content using ion chromatography. The results showed that NH4+ concentrations were higher than NO3- with the VWM concentrations of 187.23 &#956;eql-1 and 26.79 &#956;eql-1 respectively. Furthermore, wet deposition flux of NH4+-N was calculated as 4.25 kg ha-1 yr-1 while that of NO3--N was as 2.10 kg ha-1 yr-1. VWM concentrations of major ions decreased in the following order NH4+ > Ca2+ > SO42- > NO3- > K+ > Cl- > Na+ > Mg2+. In this study, relatively high NH4+ concentrations in rainwater can be attributed to nearby agricultural activities, excreta and biomass burning.Keywords: Rainwater, Neutralisation, VWM concentration, Agricultural site, Reactive Nitrogen.

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